Possible Causes & Corrections
WARNING: This page does not describe the selected car, but rather 34 other vehicles, including the 2002 Saturn Vue, 2002 Pontiac Montana, 2002 Pontiac Aztek, 2002 Oldsmobile Silhouette, and 2002 Oldsmobile Bravada. However, it is still accessible from the selected car via links, so may be relevant.
Check the following items:
- Inspect the PCM grounds for being clean, tight, and in the proper locations.
- Remove and inspect the air filter element for dirt or for being restricted.
- Inspect the Fuel Rail Pressure (FRP) sensor. Observe the FRP with a scan tool. The FRP should be between 1.1-1.4 MPa. If it is not, inspect for high resistance in the FRP sensor circuits, or the FRP sensor.
- Perform the fuel injector balance test. See appropriate SYSTEM & COMPONENT TESTING article.
- Inspect for a restriction in the fuel return system.
- Inspect for a contaminated fuel condition.
- Inspect for a sticking fuel pressure regulator. The symptom for this condition will be an idle surge of at least 100 RPM. This surge will be from 50 RPM above desired idle speed to 50 RPM below desired idle speed.
- Observe the Fuel Rail Pressure (FRP) sensor and the fuel pressure regulator commanded percent at idle. FRP should be near 40 MPa, and commanded percent should be near 40 percent. If the command is high, a fuel pressure or sensor exists.
- Inspect for an intermittent Crankshaft Position (CKP) sensor signal.
- Inspect the Crankshaft Position (CKP) sensor reluctor wheel. Remove the CKP sensor and attempt to move the reluctor wheel front to back or side to side with a probe. If there is any movement the reluctor wheel retaining bolts are loose.
- Inspect for proper crankcase ventilation.
- Check engine for low compression. Check for incorrect valve timing, bent push rods, broken valve springs or worn camshaft lobes.
- Inspect the components of the exhaust system for possible restrictions.
- Electromagnetic Interference (EMI) on the reference circuit can cause an engine miss condition. A scan tool can usually detect EMI by monitoring the engine RPM. A sudden increase in RPM with little change in actual engine RPM change indicates that EMI is present. If a problem exists, inspect routing of high voltage components, such as fuel injector wiring, near the sensor circuits.
- Inspect the Park/Neutral Position (PNP) switch circuit.
- Inspect for a short to 5 volts on one of the fuel injector control circuit between the ECM and the FICM.
- Inspect for faulty motor mounts.
- Inspect intake manifold and exhaust manifold passages for casting flash.